body{
    width: 100vw;
    height: 100vh;
    /* background-color: black; */
    margin: 0;
    padding: 0;

    font-family: Helvetica Neue, Helvetica, PingFang SC, Hiragino Sans GB, Microsoft YaHei, Arial, sans-serif;
}


.floatleft{
    float: left;
}

.floatright{
    float: right;
}

.clear{
    clear: both;
}
